Micrometer



(No Model.)

E. o. GLA-PP.

MIGROMBTER,

No. 468,642. Patented Feb. 9, 1892.`

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`lthreaded sleeve being removed.

`UNITED STATES PATENT OFFICE,

EDVARD CLIFTON CLAPP, OF ATHOL, MASSACHUSETTS.

MICROMETER.

SPECIFICATION forming part of Letters Patent No. 468,642, dated February9, 1892. Application led May ll, 1891. Serial No. 392,352. (No model.)

To @ZZ whom z5 may concern.l

Be it known th at 1, ED WARD CLIFTON CLAPP, a citizen of the UnitedStates, and a resident of Athol, in the county of forcester and State ofMassachusetts, have invented certain new and useful Improvements inMicrometers; and I do hereby declare that the following is a full,clear, and exact description of the invention, which will enable othersskilled in the art to which it appertains to make and use the same,reference being had to the accompanying drawings, which form a part ofthis specification. Y

My invention relates to improvements in measuring-instruments of thatclass known as micrometers, by means of which measurements may be madewith great exactness.

The object of the invention is to provide an instrument of the abovecharacter in which the head-stock carrying the micrometer-screw ismovable upon a graduated beam, so that it can be readily and quicklyadjusted to varying lengths of articles to be measured, said lengthsbeing indicated by the graduated beam.

The invention consists in the novel construction and combination ofparts l1ereinat`- ter fully described, and specifically pointed out inthe claims.

In the accompanying drawings, Figure 1 is a perspective View of ameasuring-instrument constructed in accordancewith my invention. Fig.4 2is a perspective view of the movable head-stock detached, the spindleand screw- Fig. 3 is a sectional View of the hollow split tube. Fig. 4is a sectional view of the spindleand sleeve on a slightlya'educedscale. Fig. 5 is a detail View of one oi' the beam-studs and its securing-screw. Fig. G is a crosssection of the instrument taken through themovable headstock.

In the said drawings the referencenumeral 1 designates a head-stockhaving a stud 2 at its upper end and secured near its lower end to thebeam 3. Thisl beam is provided with a longitudinal dovetailed groove 4,in which is inserted a series of correspondiugly-shaped bars or plates5, having outwardly-projecting lugs or stops 6. These stops are arrangedat equal distances apart-say half-inches-and the beam is provided withcharacters indicating the distance of said stops from the xedhead-stock. The plates 5 are movable in the groove, so as to compensatefor wear, and are u held in place by the studs 7, set in recesses in thebeam and having central recesses, through which pass binding-screws S.These studs have a portion of their peripheries attened to engage withthe plates, as seen in Fig. 5.

The numeral 9 designates the movable crosshead, having anopeningcorresponding in shape with the` beam which passes therethrough,so that said cross-head can be reciprocated thereon. The face ot` thecrosshead is also cut away, as shown, leaving a downwardly-dependingshoulder 10,Which engages one of the lugs or stops 6. The lower part ofthe cross-.head is also provided or formed with a chamber 12, in whichis located a verticallymovable plate 13, having transverse grooves 14E214-, through which pass pins 15 15. Through the lower end of thecrosshead passes aset-screw 1G, which engages with the plate 13, and bymeans of which the latter may be adjusted vertically. The object of thegrooves 14 14 is to allow the plate 13 to be moved or adjusted withoutinterfering with the pins 15.

In the upper part of the cross-head D is secured a hollow tube 17,having its outer end split and formed with a number of micrometerscrewthreads 18. The exterior of this tube intermediate of its ends isprovided with a number of parallel graduations, as is usual in thischaracter of instruments. Passing through this tube is a spindle 19,upon the outer end of which is mounted a sleeve 20,

having a milled head 21. The interior of this sleeve is formed with aseries of screw-threads corresponding with those on the tube 17. Theperiphery of the sleeve is provided with a series of indicatingcharacters 22, as usual. The outer end of the hollow tube 17 isinteriorly screw-threaded to receive a hollow plug 23, having an angularshoulder 24, by means of which the split ends of said tube may be forcedoutward to compensate for wear. j

The operation will be readily understood. The movable cross-head isadjusted by loosening the screw 16 and moving it upon the beam theproper distance to receive the article to be measured, with the shoulder10 rest- ICO ing against one of the stops G, as seen in Fig. l. 4Thescrew is then tightened, whereby said head-stock is securely held inplace and the article to be measured is inserted between thehead-stocks. By means of the graduations on the beam the distancebetween the stud 2 on the stationary head-stock and the movablehead-stock can be readily ascertained, and iu connection with thespindle and micrometerscrew the length of the article can be measuredwith great exactness and accuracy.

Having thus described my invention, what I claim isl. In ameasuring-instrument, the combination, with the stationary head-stock,the beam secured thereto, having a dovetailed groove, and theremovablefplates seated in said grooves, having projecting lugs orstops, of the movable head-stock mounted on said beam and provided witha shoulder, substantially as described.

2. In a measuring-instrument, the combination, with the head-stock andthe graduated beam secured thereto, of the movable headstock having anopening therethrough for the passage of the beam, cut away on its face,and provided or formed with a depending shoulder, the vertically-movableplate located iu a chamber in the lower end of said head-stock, theset-screw, and the proj ectinglugs or stops on the beam adapted toengage with said depending shoulder, substantially as described.

3. In la measuring-instrument, the combination, with thehead-stock andthe graduated beam secured thereto, having a longitudinal groove, of themovable head-stock having an opening therethrough for the passage of thebeam, cut away on its face, and provided with a depending shoulder, themovable plates 1ocated in the groove in the beam and having projectinglugs or stops, the studs having a portion of the periphery iiattened andhaving central apertures, and the screws for securing said studs inrecesses in the beam, substantially as described.

4. In a measuring-instrument, the combi` nation, with the head-stockan-d the graduated beam secured thereto and having a longitudinal grooveand a series of movable plates with projecting stops, of the movablehead-stock having an opening therethrough to receive the beam and cutaway on its face andEl provided with a depending shoulder, thevertically-movable plate located in a chamber in said head-stock, havingtransverse grooves therein, the transverse pins passing through thehead-stock, and the set-screw for adjusting said plate, substantiallyasdescribed.

In testimony that I claim the foregoing as my own I have hereuntoaffixed my signature in presence of two witnesses.

E'DVARD CLIFTON CLAIP.

lVitnesses:

FREDERICK ACnnrr, EMMA M. WILSON.

